Port Round 2 to Java (OrderBook): 14 tests total green, START state preserved

2026-10-01 13:38:42 +01:00
parent f927998149
commit 2831b8c3f9
5 changed files with 259 additions and 0 deletions
@@ -25,5 +25,11 @@
      <version>${junit.version}</version>
      <scope>test</scope>
    </dependency>
+    <dependency>
+      <groupId>org.assertj</groupId>
+      <artifactId>assertj-core</artifactId>
+      <version>${assertj.version}</version>
+      <scope>test</scope>
+    </dependency>
  </dependencies>
 </project>
@@ -0,0 +1,121 @@
+package orderbooktests;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+
+import org.junit.jupiter.api.Test;
+
+import orderbookdomain.OrderBook;
+import orderbookdomain.OrderStatus;
+
+class OrderBookLifecycleTests {
+
+    private static final Instant DAY_0 = Instant.parse("2025-06-01T00:00:00Z");
+
+    private static Instant at(int day) {
+        return DAY_0.plus(day, ChronoUnit.DAYS);
+    }
+
+    @Test
+    void finalizeThenPay_movesOrderThroughTwoStates() {
+        OrderBook book = new OrderBook();
+        var order = book.openOrder("anna");
+
+        book.finalizeOrder(order.getId(), at(1));
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.WAITING_FOR_PAYMENT);
+
+        book.payOrder(order.getId(), at(2));
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.FULFILLING);
+    }
+
+    @Test
+    void payThenShip_deliversTheOrder() {
+        OrderBook book = new OrderBook();
+        var order = book.openOrder("anna");
+
+        book.finalizeOrder(order.getId(), at(1));
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.WAITING_FOR_PAYMENT);
+
+        book.payOrder(order.getId(), at(2));
+        book.shipOrder(order.getId());
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.DELIVERED);
+    }
+
+    @Test
+    void payWithinWindow_thenLatePayOnSecondOrder_cancelsOnlyThatOrder() {
+        OrderBook book = new OrderBook();
+        var first = book.openOrder("anna");
+        var second = book.openOrder("bram");
+
+        book.finalizeOrder(first.getId(), at(1));
+        book.finalizeOrder(second.getId(), at(1));
+        assertThat(book.getOrders()).hasSize(2);
+
+        book.payOrder(first.getId(), at(5));
+        assertThat(book.getOrder(first.getId()).getStatus()).isEqualTo(OrderStatus.FULFILLING);
+
+        assertThatThrownBy(() -> book.payOrder(second.getId(), at(30)))
+            .isInstanceOf(IllegalStateException.class);
+        assertThat(book.getOrder(second.getId()).getStatus()).isEqualTo(OrderStatus.CANCELLED);
+    }
+
+    @Test
+    void payBeforeFinalize_throws_thenFinalizeStillWorks() {
+        OrderBook book = new OrderBook();
+        var order = book.openOrder("anna");
+
+        assertThatThrownBy(() -> book.payOrder(order.getId(), at(1)))
+            .isInstanceOf(IllegalStateException.class);
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.PENDING);
+
+        book.finalizeOrder(order.getId(), at(2));
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.WAITING_FOR_PAYMENT);
+    }
+
+    @Test
+    void cancelPendingOrder_thenPayAfterCancel_throwsAgain() {
+        OrderBook book = new OrderBook();
+        var order = book.openOrder("anna");
+
+        book.cancelOrder(order.getId());
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.CANCELLED);
+
+        assertThatThrownBy(() -> book.payOrder(order.getId(), at(1)))
+            .isInstanceOf(IllegalStateException.class);
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.CANCELLED);
+    }
+
+    @Test
+    void shippedOrder_cannotBeCancelled() {
+        OrderBook book = new OrderBook();
+        var order = book.openOrder("anna");
+
+        book.finalizeOrder(order.getId(), at(1));
+        book.payOrder(order.getId(), at(2));
+        book.shipOrder(order.getId());
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.DELIVERED);
+
+        assertThatThrownBy(() -> book.cancelOrder(order.getId()))
+            .isInstanceOf(IllegalStateException.class);
+        assertThat(book.getOrder(order.getId()).getStatus()).isEqualTo(OrderStatus.DELIVERED);
+    }
+
+    @Test
+    void twoCustomers_interleaveTransitions_independently() {
+        OrderBook book = new OrderBook();
+        var annas = book.openOrder("anna");
+        var brams = book.openOrder("bram");
+
+        book.finalizeOrder(brams.getId(), at(1));
+        assertThat(book.getOrder(annas.getId()).getStatus()).isEqualTo(OrderStatus.PENDING);
+        assertThat(book.getOrder(brams.getId()).getStatus()).isEqualTo(OrderStatus.WAITING_FOR_PAYMENT);
+
+        book.payOrder(brams.getId(), at(2));
+        book.cancelOrder(annas.getId());
+        assertThat(book.getOrder(annas.getId()).getStatus()).isEqualTo(OrderStatus.CANCELLED);
+        assertThat(book.getOrder(brams.getId()).getStatus()).isEqualTo(OrderStatus.FULFILLING);
+    }
+}